osTicket admin login denied

My YunoHost server

Hardware: VPS on a server
YunoHost version: 4.3.6.3
I have access to my server : Through SSH | through the webadmin
Are you in a special context or did you perform some particular tweaking on your YunoHost instance ? : no

Description of my issue

When I install #osTicket I choose a password for the admin, but when I try to login with this user/password or with admin/password I get:
Zugang verweigert (Access Denied)

Is there a special page to go to for the login that is not this one?

Other question, is there another #Ticketsystem besides #osTicket for Yunohost that you can suggest. I am considering to use #Redmine, but am not sure how well it works as a ticket system for #email support.

Thanks for any help.

I wonder if anyone can reproduce this issue? Just install the app and let me know if it works for you!